1. Field of the Invention
The present invention relates to a non-flamable adhesive composition and, more particularly, to a non-flamable adhesive composition appropriate for use on the manufacture of, in particular, flexible printed circuit boards.
2. Brief Description of Prior Art
Polyimide series films, unlike other plastic films, have a combination of, particularly, outstandingly superior heat resistance and dimensional stability with non-flamability. Accordingly, if such polyimide series films would be applied to flexible printed circuit boards by allowing a metal foil for conductive pattern to adhere to the films, they will provide accurate printed circuits which require high dimensional accuracy or precision in processing and which are appropriate for use on circuit boards for machinery and tools that require heat resistance under operational conditions.
Heretofore, although a number of adhesives having superior electrical performance and high adhesion for printed circuits have been proposed, little attempts have been so far made to have adhesives non-flamable making the best use of the non-flamable characteristics of the polyimide series films satisfying the requirements according to Underwriters Laboratory (UL) Standards 94V-O with respect to non-flamability. Many states of the United States of America require electrical appliances, by laws, to satisfy the UL Standards and procure the grant of the UL Standards Recognition. Thus, plastics to be used for electrical and electronical parts and apparatuses are required to be rendered non-flamable.